RU1770762C - Two-channel level indicator - Google Patents

Abstract

Usage: the invention relates to instrumentation, specifically to devices for monitoring the level of electrically conductive liquids. SUMMARY OF THE INVENTION: an alternating current flows through the sensor electrodes in the device, which extends its life, there is also a second information channel, which is turned on when the sensor electrodes are opened. 1 ill.

Description

The invention relates to level control devices and can be used to signal the level of an electrically conductive liquid in vessels under pressure or atmospheric pressure.

A known level transmitter of conductive liquids containing an electrode sensor and a sensor signal processing circuit made on thyristors (U.S. Patent No. fsfe 3206615, CL 307-885, 1965).

Its disadvantage is that a unipolar pulsating current passes through the electrode sensor during operation, which leads to the destruction of the sensor during operation, due to polarization and electrocorrosion.

Known level switch for ed. St. No. 605103, comprising an electrode sensor, two on-parallel thyristors, the control electrodes of which are connected to diodes, interconnected by cathodes, an alternating current source and a load. This level switch is selected as a prototype.

The prototype operates as follows.

When the liquid level reaches the sensor electrodes, a unipolar pulsating current will flow through the conducting liquid along the circuit: the midpoint of the voltage divider of the diode anodes is the control electrodes of the thyristors, which alternately open and close the load circuit to the power buses. At the same time, a unipolar pulsating current flows through the sensor electrodes. When the liquid level decreases, the signal to the control electrodes of the thyristors stops, and the current through the load is interrupted. In the prototype, the range of application has been expanded and the reliability of the level switch has been increased. However, here too, polarization of the electrodes and their electrocorrosion takes place.

The aim of the invention is to increase the life of the level switch and provide additional information.

The essence of the invention is that in the level switch there are two thyristors and two diodes connected by anodes, the cathode of the third additional diode and one of the sensor electrodes are connected to the anodes of these diodes, and the second sensor electrode is connected to the first power bus, to

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which simultaneously connects the anode of the first & thyristor and the cathode of the second thyristor, while the cathode of the first thyristor is connected to the load of the first information channel in the form of a signal light, and the anode of the second thyristor is connected to another information channel, also in the form of a light bulb, the second terminals of these lights are connected to a second power rail, which is connected through a resistor to the anode of the third additional diode. New in the inventive signaling device are new interconnections of elements, where when the sensor electrodes are closed with a controlled liquid in one half-cycle, the current passes through the sensor electrodes, then through the corresponding diode and control electrode of the first thyristor, which, when opened, includes the first information channel in the form a light bulb, and in the second half-cycle, the current will flow from another power bus through a resistor and an additional diode to the sensor electrodes, while the first thyristor is closed and the second thyristor does not open until x, until the level of the monitored liquid decreases and the circuit of the sensor electrodes opens, only at this time the current will pass from the other power line through the resistor and an additional diode, then through another corresponding diode and a control electrode of the second thyristor, which in turn will open and The bulb of the second information channel will turn on, and with another half-cycle this thyristor will close and there will be no current and then open again when the half-cycle is changed.

Thus, the reliability of the claimed device is higher, since when the electrodes are closed, alternating current will flow through them, at the same time the information content of such a level switch is higher, since the first thyristor and the lamp of the first information channel will turn on through the sensor’s wet contacts (the second one does not work at this time) ), and when the sensor contacts are dry, the second thyristor and the bulb of the second information channel from a pulse of a different polarity are turned on (the first is not working at this time), the drawing shows the electric ska diagram of the inventive bi-layer signaling.

The drawing shows the inventive signaling device.

The signaling device is a cell with two information channels, for example, in the form of signal lights 10.11, in addition there is an electrode sensor 7, two thyristors 1 and 2, three diodes 5.6 and 9, and

also a resistor 8 and two AC power buses 3 and 4.

The signaling device operates as follows.

After applying the supply voltage, when the electrodes of the sensor 7 are dry, channel 11 will turn on for one half-cycle through the circuit: power bus - diode 8 - Common point 12 - diode b - control electrode of thyristor 2 - bus 3. Thyristor 2 will open and turn on lamp of channel 11, During another half-cycle, thyristor 2 will be closed and there will be no current, and when it is changed, thyristor 2 will reopen. When closed

5 of the electrode sensor 7 with a controlled fluid, i.e. when the sensor contacts are wet, channel 10 will turn on in the half-cycle opposite to the first channel, along the circuit: power bus 3 - electrodes

0 of the sensor 7 - common point 12 - diode 5 - control electrode of thyristor 1 - channel 10 - power bus 4, - thyristor 1 will open and the lamp of channel 10 will turn on.

In another half-cycle, thyristor 1 closes and there will be no current through it, and the current through the wet electrodes of the sensor will flow through the circuit: bus 3 - register 8 - diode 9 - common point 12 - electrodes of the sensor 7 - power bus 3. When changing the half-cycle

0, thyristor 1 will open again and current will pass through the lamp of channel 10.

At all times, when the electrodes of the sensor 7 are closed, they bypass the switching circuit of the thyristor 2 and the bulb 5 of the channel 11 is turned on.

Thus, when the sensor electrodes are dry, the light of one information channel is turned on, and when the electrodes are wet, i.e. closed controlled

0 liquid, the first channel is turned off, and the bulb of the second channel is turned on, while alternating current pulsates through the sensor electrodes. This ensures the reliability of operation and expanded the range of information content.

Claims (1)

SUMMARY OF THE INVENTION A two-channel level switch comprising an electrode sensor with first and second electrodes, a first and a second 0 counter-parallel connected thyristors, the control electrodes of which are connected to the cathodes of the first and second diodes, interconnected by anodes, to which one of the sensor electrodes 5 is connected, an alternating current source with the first and second buses and an indicator, characterized in that, with In order to increase durability and reliability, a diode and a resistor connected in series are additionally introduced into it, and the indicator is made in the form of the first and second lamps, while the diode cathode is connected to the anodes of the first and second diodes, the resistor a second bus Inonii source AC current, the second electrode of the sensor is connected to the first bus, the anode of the first thyristor and the cathode of the second thyristor, and the cathode of the first thyristor and through the second lamp the anode are connected to the second bus